What approach did Marks et al. (2005) use to study the environmental influence on aggression in zebrafish?

A) They compared the behavior of parents and offspring raised in different environments.
B) They selected for aggressive behavior in different environments.
C) They observed the aggressive behavior of populations that live in different environments.
D) They observed aggression in one population that was exposed to two different environments.
E) They exposed genetically similar individuals to different environments and compared their aggression.